Abstract: A valve timing system and method 10 is provided which automatically compensates for variations in the compression ratios of cylinders 12 of an internal combustion engine 30. Valve timing system 10 includes a controller 24 and actuators 26, 28 which selectively actuate valves 14, 16 in response to signals received from controller 24. In one embodiment, controller 24 is effective to cause each of the cylinders 12 to have a substantially uniform susceptibility to knock.